1. Field of the Invention
The present invention relates generally to nuclear fuel rod identification and traceability and, more particularly, is concerned with a method and apparatus for reading lased bar codes on shiny-finished fuel rod cladding tubes.
2. Description of the Prior Art
Various techniques have been proposed in the past to identify specific nuclear fuel rods for different purposes. For instance, in U.S. Pat. No. 3,747,959, physical markings, such as indentations or notches, are used for object identification. In U.S. Pat. No. 4,636,846, fuel rods are stamped with indicia in the form of a character code prior to insertion into the reactor for the purpose of identifying each fuel rod upon removal after irradiation.
Bar code labels used for identifying retail products have also been used for identification of nuclear fuel rods. For instance, in U.S. Pat. No. 4,587,407, bar code labels are affixed to nuclear fuel rod claddings which contain information such as an individual identification number assigned to the particular fuel rod. The bar code is adapted to be optically scanned and read to determine its assigned number. The bar code labels were employed for traceability of a fuel rod during its manufacture. The labels are manually applied at the start of the manufacturing process and manually removed at the end. Thus, there was no continued traceability of individual fuel rods after completion of manufacturing.
The use of bar codes would appear to have great promise for identification and traceability of individual fuel rods. However, their application on labels has shortcomings. The labels are costly to apply and remove. The labels will not stay on while the fuel rods are in use in a nuclear reactor.
Up to the present time, none of the prior techniques have addressed the traceability of individual fuel rods in a totally comprehensive manner. Consequently, a need exists for a comprehensive approach to identification of fuel rods so that individual fuel rods can be traced during any stage in their manufacture and use.